Liquid Biopsy Detects Relapse Five Months Earlier than Regular Clinical Follow-Up and Guides Targeted Treatment in Breast Cancer.

Genetic alterations in circulating tumor DNA (ctDNA) are an emerging biomarker for the early detection of relapse and have the potential to guide targeted treatment. ctDNA analysis is often performed by droplet digital PCR; however, next-generation sequencing (NGS) allows multigene testing without having to access a tumor sample to identify target alterations. Here, we report the case of a stage III hormone receptor-positive breast cancer patient who remained symptomless after receiving surgery and adjuvant chemotherapy. Liquid biopsy analysis by NGS revealed the presence of a ctDNA PIK3CA N345K mutation five months before the detection of relapse with multiple liver metastases by regular clinical follow-up. To date, clinical implications of the PIK3CA N345K variant remain insufficiently investigated; however, everolimus treatment resulted in the shrinkage of tumor lesions and decreased the levels of tumor markers. Four months after treatment initiation, a second ctDNA analysis suggested a relapse, and the patient clinically progressed after five months of everolimus therapy. This case report demonstrates the value of ctDNA analysis by NGS for the early detection of relapse in breast cancer patients. The study further indicates its usefulness for the choice of targeted treatments, suggesting that the variant PIK3CA N345K might be associated with everolimus sensitivity.

Concomitant Genetic Alterations are Associated with Worse Clinical Outcome in EGFR Mutant NSCLC Patients Treated with Tyrosine Kinase Inhibitors.

Epidermal growth factor receptor- tyrosine kinase inhibitors (EGFR-TKI) are recommended first-line therapy for advanced non-small cell lung cancer (NSCLC) with sensitizing EGFR mutations. It is of clinical interest to identify concurrent genetic mutations in NSCLC patients with EGFR mutations in the hopes of discovering predictive biomarkers towards EGFR-TKI treatment. We retrospectively analyzed a cohort of patients with advanced EGFR mutant NSCLC who underwent treatment with first generation TKIs at our hospital by a multi-gene panel via next generation sequencing. A total of 33 patients with mutant EGFR were enrolled. Up to 26 (78.8%) patients had at least one concomitant genetic alteration coexisting with mutant EGFR. Among the concomitant genetic alterations discovered, TP53 mutation was most common (n = 10,30.3%), followed by CDK4 (n = 8, 24.2%) and CDKN2A (n = 7, 21.2%)copy number variation (CNV). Progression-free survival was shorter in patients with concomitant FGFR3 mutation (1.6 vs. 12.6 months, P = .003) and CDKN2A CNV loss (6.5 vs. 13.4months, P = .019). Patients with any concomitant genetic alterations also had significant worse overall survival (24.1 vs. 40.8 months, P = .029). In summary, our study revealed an unfavorable association between concomitant genetic mutations and treatment response towards EGFR-TKI. FGFR3 mutation and CDKN2A CNV loss may be potential predictive markers for treatment outcome and warrant further investigation.

Downregulation of miR-29 contributes to cisplatin resistance of ovarian cancer cells.

Drug resistance is an obstacle to the treatment of ovarian cancer. Using a unique cell model, we have proven previously that a subpopulation of ovarian cancer cells is more resistant to cisplatin than are the original cells. MicroRNAs (miRNAs), small noncoding RNAs, are involved in many biological events in cancer cells. In our study, we explored whether miRNAs are involved in cisplatin resistance of ovarian cancer cells. Cisplatin-resistant cells expressed a lower level of miR-29a/b/c. Manipulation of microRNA-29 (miR-29) expression modulated cisplatin sensitivity of CP70, HeyC2, SKOV3 and A2780 ovarian cancer cells. Knockdown of miR-29a/b/c increased the ability of cells to escape cisplatin-induced cell death partly through upregulation of collagen type I alpha 1 (COL1A1) and increased the activation of extracellular signal-regulated kinase 1/2 and inactivation of glycogen synthase kinase 3 beta. When combined with cisplatin treatment, knockdown of miR-29 decreased the amount of the active form of caspase-9 and caspase-3. Ectopic expression of miR-29 alone or in combination with cisplatin treatment efficaciously reduced the tumorigenicity of CP70 cells in vivo. Our data show that downregulation of miR-29 increases cisplatin resistance in ovarian cancer cells. Taken together, these data suggest that overexpression of miR-29 is a potential sensitizer to cisplatin treatment that may have therapeutic implications.

The role of Sp1 and EZH2 in the regulation of LMX1A in cervical cancer cells.

We have reported previously that LIM homeobox transcription factor 1α (LMX1A) is hypermethylated and functions as a metastasis suppressor in cervical cancer cells. However, the regulation of LMX1A in carcinogenesis has not been reported. We aim to clarify whether specificity protein 1 (Sp1) and enhancer of zeste homolog 2 (EZH2) are involved in the regulation of LMX1A in cervical cancer. First we characterized the LMX1A promoter and used overexpression, knockdown, and reporter assays to show that Sp1 increased LMX1A promoter activity. Next, we used site-directed mutagenesis and electrophoresis mobility shift assays (EMSAs) to demonstrate that Sp1-binding sites were important for Sp1-mediated activation of the LMX1A promoter. Chromatin immunoprecipitation data demonstrated that Sp1 could bind directly to the LMX1A promoter and activate endogenous LMX1A expression in cells pretreated with 5-aza-2'-deoxycytidine (5-aza-dC). Knockdown of EZH2 decreased H3K27me3 histone modification but was insufficient to restore LMX1A expression. To explore the effect of EZH2 on the endogenous LMX1A promoter, we treated EZH2-knockdown cells with 5-aza-dC and trichostatin A (TSA) and then depleted the cells of drugs for 3days. H3K14ac was enriched at the LMX1A promoter in EZH2-knockdown cells and LMX1A mRNA was still expressed. Taken together, these data imply that Sp1 may activate LMX1A expression upon oncogenic stress during cervical cancer development. Moreover, suppression of EZH2 may delay resilencing of LMX1A after the removal of 5-aza-dC and TSA.

SOX1 suppresses cell growth and invasion in cervical cancer.

OBJECTIVE: Abnormal activation of the Wnt/ß-catenin signaling pathway is common in human cancers, including cervical cancer. Many papers have shown that SRY (sex-determining region Y)-box (SOX) family genes serve as either tumor suppressor genes (TSGs) or oncogenes by regulating the Wnt signaling pathway in different cancers. We have demonstrated recently that epigenetic silencing of SOX1 gene occurs frequently in cervical cancer. However, the possible role of SOX1 in cervical cancer remains unclear. This study aimed to explore whether SOX1 functions as a TSG in cervical cancer. METHODS: We established a constitutive and an inducible system that overexpressed SOX1 and monitored its function by in vitro experiments. To confirm SOX1 function, we manipulated SOX1 using an inducible expression approach in cell lines. The effect of SOX1 on tumorigenesis was also analyzed in animal models. RESULTS: Overexpression of SOX1 inhibited cell proliferation, anchorage independency, and invasion in vitro. SOX1 suppressed tumor growth in nonobese diabetic/severe combined immunodeficiency mice. After induction of SOX1 by doxycycline (DOX), SOX1 inhibited cell growth and invasion in the inducible system. Repression of SOX1 by withdrawal of DOX partially reversed the malignant phenotype in cervical cells. SOX1 inhibited TCF-dependent transcriptional activity and the Wnt target genes. SOX1 also repressed the invasive phenotype by regulating the expression of invasion-related genes. CONCLUSIONS: Taken together, these data suggest that SOX1 can function as a tumor suppressor partly by interfering with Wnt/ß-catenin signaling in cervical cancer.

SOX1 functions as a tumor suppressor by antagonizing the WNT/ß-catenin signaling pathway in hepatocellular carcinoma.

UNLABELLED: Oncogenic activation of the Wnt/ß-catenin signaling pathway is common in hepatocellular carcinoma (HCC). Our recent studies have demonstrated that SRY (sex determining region Y)-box 1 (SOX1) and secreted frizzled-related proteins are concomitantly promoter-hypermethylated, and this might lead to abnormal activation of the Wnt signaling pathway in HCC. SOX1 encodes a transcription factor involved in the regulation of embryonic development and cell fate determination. However, the expression and functional role of SOX1 in HCC remains unclear. In this study, we confirmed via quantitative methylation-specific polymerase chain reaction that SOX1 was frequently downregulated through promoter hypermethylation in HCC cells and tissues. Overexpression of SOX1 by a constitutive or inducible approach could suppress cell proliferation, colony formation, and invasion ability in HCC cell lines, as well as tumor growth in nonobese diabetic/severe combined immunodeficiency mice. Conversely, knockdown of SOX1 by withdrawal of doxycycline could partially restore cell proliferation and colony formation in HCC cells. We used a T cell factor (TCF)-responsive luciferase reporter assay and western blot analysis to prove that SOX1 could regulate TCF-responsive transcriptional activity and inhibit the expression of Wnt downstream genes. Furthermore, we used glutathione S-transferase pull-down, co-immunoprecipitation, and confocal microscopy to demonstrate that SOX1 could interact with ß-catenin but not with the ß-catenin/TCF complex. Moreover, restoration of the expression of SOX1 induces significant cellular senescence in Hep3B cells. CONCLUSION: Our data show that a developmental gene, SOX1, may function as a tumor suppressor by interfering with Wnt/ß-catenin signaling in the development of HCC.

Transgenic expression of single-chain anti-CTLA-4 Fv on beta cells protects nonobese diabetic mice from autoimmune diabetes.

T cell-mediated immunodestruction of pancreatic beta cells is the key process responsible for both the development of autoimmune diabetes and the induction of rejection during islet transplantation. In this study, we investigate the hypothesis that transgenic expression of an agonistic, membrane-bound single-chain anti-CTLA-4 Fv (anti-CTLA-4 scFv) on pancreatic beta cells can inhibit autoimmune processes by selectively targeting CTLA-4 on pathogenic T cells. Strikingly, transgenic expression of anti-CTLA-4 scFv on pancreatic beta cells significantly protected NOD mice from spontaneous autoimmune diabetes. Interestingly, local expression of this CTLA-4 agonist did not alter the diabetogenic properties of systemic lymphocytes, because splenocytes from transgenic mice or their nontransgenic littermates equally transferred diabetes in NOD/SCID recipients. By analyzing the T cell development in anti-CTLA-4 scFv/Th1/Th2 triple transgenic mice, we found that beta cell-specific expression of CTLA-4 agonist did not affect the development of Th1/Th2 or CD4(+)CD25(+) regulatory T cells. Most strikingly, islets from transgenic mice inhibited T cell response to immobilized anti-CD3 in a T cell-islet coculture system, suggesting a trans-mediated inhibition provided by transgenic islets. Finally, transgenic islets implanted in diabetic recipients survived much longer than did wild-type islets, indicating a therapeutic potential of this genetically modified islet graft in autoimmune diabetes.